Telegraph system



J. H. BELL.

TELEGRAPH SYSTEM.

APPLICATION FILED OCT. 11, 1911.

1,359,565, Patented Nov. 23, 1920.

t 2 SHEETSSHEET 1.

41 if I 4/17 J. H. BELL.

TELEGRAPH SYSTEM.

APPLICATION FILED OCT. 11. 1917.

Patented Nov. 23, 1920,

2 SHEETS-SHEET 2.

/ Mar i g l C Marginal W e/1 for. down 6 6e UNITED STATES PATENT Qr'l 'lQE.

JOHN H. BELL, OF SOUTH ORANGE. NEVT JERSEY, ASSIGNOB, TO WESTERN ELEGTBIC GUMIANY, INCORPORATED, 013 NEW YORK, N. Y., A GORPGRATION OF NEW YORK.

TELEGRAPH SYSTEM.

1,359,565, Specification c Letters Patent Patented Nov. 23, 12 E2 9.

Application filed october 11, 1917. Serial No. 195,916.

T all from it may concern Be it Known that 1, JOHN H. BELL; a citizen of the United States residing at South Orange, in the county of Essex and State of New Jersey, have invented certain new ano useful Improvements in Telegraph Systems, oi which the following isa full, clear, concise, and exact description.

This invention relates to telegraph systems, and more particularly to improve ments in telegraph transmitting systems for use with circuits having low time constant characteristics, such as submarine cable circuits.

The principal object of this invention is to provide improved apparatus and systems to overcome the phenomena of electrical distortion inherent in submarine cable telegraphy.

Tn submarine cable telegraphy it is a wellestablished fact that the speed of working and the quality of definition or distinctive ness of received signals is dependent on the extent to which a cable be maintained free from excess charge of either polarity during brief time intervals, or at a true zero current condition with respect to the polarities of impulses of current employed in transmission.

W1 11 the signal combinations consist of unbro n reversals of current in which certain h; f-waves are incremented it is true that when two incremented half-waves of the same polarity are separated by a half-wave oi nori'nal amplitude, the second incremented halt-wave will produce a signal, say, on a siphoi recorder tape, having an amplii-Zlilfi V ir 'ernented impulse. This is, of course, e to the fact that a portion of the first incremented impulse charge'is retained by the cable and not overcome or properly rednceiil by the intervening inverse impulse of less strength and accordinglysuch charge an ments the second incremented impulse, ther by distorting the zerov condition of the cable.

The present invention contemplates the application of curbing effects to the regular signaling impulses in a manner to render each current impulse effective as a message transmitting impulse. The corrective scope the present invention and the gain in transmission speed effected are such that im- 5 pulse receiving means sufficiently effective ater than should be attained by such for the control of a receiving printer may be reliably and efficiently operated, thereby ex tending the iield of printing telegraphs to commercial cable operation.

To the above end, there is provided, in connection with a source of periodic alternating),- currents, preferably of sine wave form. the usual transmittinp' contacts, a plurality 0t electroresponsive switching devices and distrihuter means to selectively control the strength of current impulses impressed on a cable circuit for message transmission. In connection with the message transmission equipment, other electroresponsive switchdevices are automatically controlled thereby in a manner to further modify the strength oi? certain message impulses in a manner to prevent an asymmetrical Zero polarity effect in a cable, as already pointed out.

This invention is illustrated diagrammatically in the accompanying drawing, in which only so much of a telegraphic equipment is shown as will be necessary to a clear understanding of the system.

In the drawing Figure 1 illustrates a trairemitting equipment suitable for practising the features of this invention; Fig. 2 illustrates the wave form of alternating; currents with curves to indicate modifications thereoi effected through the present system; and Fig. illustrates an alternate arrangement of the transmitting equipmentwhich may be substituted for the equipment shown in 1.

Fieferring to the drawing, Fig. 1, a cable indicated by the reference character 13, is connected through a winding: 15 of a transformer 14 to an earth connection 17. A second winding 16 of the transformer is included in a closed loop formed, through a resistance unit 19 and a single phase alternating current generator 18. A grounded source of current is connected by way of a bus conductor with five transmitting contacts collectively indicated as a group A, and preferably arranged to be controlled by means of a punched tape as well understood in the art.

For convenience in illustrating, the prescnt invention herein shown as applied to a transmitting; system wherein each character, symbol or other operation transmitted, is distinguished from all other characters, symbols or operations through a particular permutation of five impulses of current of normal or incremented strcngtl A magnet 53 connected tothe current bus 34: is controlled through segments 55 and 56 of a dist ibuter E for operating suitable mechanism (not shown) to step or advance a punched tape which may be assumed as present for controllin 'the operation of the contacts A, as already mentioned. A. group of five relays B controlled by the contacts A pre pare circuits to five segments of the distributer E and also control the operation of five relays comprising a group G. The relays C control. the inclusion or exclusion of resistance units comprising a group D in respective circuits prepared to the segments of the distributor E by the relays B.

The distributer E may be of any suitable form and assuming it to be or a rotary type the contactor brushes 38 and 39 thereof would be carried clockwise by a radical arm rotated in synchronism with the generator 18. The synchronous relation is to be such that the Zero current potential moments between the alternations of a current cycle occur at such times as the brush 38 is leaving one segment and passing to a next segment. It is also provided that following the transmission of five successive character selecting impulses the brush 39 will engage the segments 55 and 56 to operate the tape control magnet 53 during a zero-potential instant of the generator 18. It will be obvious that the synchronous relation described may result in maintaining a fixed polarity relation between the generator and the transmitter contacts A and in turn with the five transmitting segments of the distributer. For the purpose of simplifying the description, a polarity rela tion has been assumed and the contacts A and the segments of the distributer correspondingly marked with the conventional polarity signs. a

By way of a first illustration let it be assumed that a non-perforated portion of the control tape is present at the contacts A and that all 01": the contacts remain open during a five impulse interval. In this case the relays B and C thereby remain unoperated and five impulses of current developed by the generator 18 will only circulate in the loop cir cuit formed through the resistance unit 19, and the transformer winding 16. In phase with the assumed polarity arrangement, as marked at the contacts A, the five impulses would progress as positive, negative, positive, negative and positive, and, due to the presence of the resistance unit 19, each impulse would be, of predetermined minimum strength. As translated tothe winding 15 of the transtorm'er five corresponding impulses would traverse the cable 13 in the form of symmetrical alternating currents, and, assuming that the speed of the generator 18 is such that the current frequency is at a proper ratio to the time constant of the cable, such currents will maintain a uniform electrical condition or true zero therein, the wave form of the currents being indicated at F in Fig. 2 of the drawing. During such five-impulse interval the brushes 38 and 39 will move as usual and following the fith impulse the brush 39 will pass over the segments 55 and 56, thereby completing a circuit through a conductor 54 and the tape control magnet 53 to the current source 33, thereby advancing the tape to establish a next combination of five impulses at the contacts A.

For the purpose of a second illustration, let it now be assumed that perforations at the present position of the transmitter tape resuit in closing each one of the contacts A. In this position. current from the source 33 through the'bus conductor 34 traverses contacts l, 21, ll, 61 and 81 to respectively operate the relays 2, 22, 42, 62 and 82. Separation of contacts l, 24, 4A, 64: and 84 of these relays respectively disconnect the relays 26, it 66, 86 and 6. The normalcontacts 7, 27, 47, 67 and 87 of the relays C accordingly remain closed, thereby including a bus conductor-35, extending in derived circuit from the closed circuit loop of the generator 18, by

way of respective contacts 3, 23, 43, 63 and.

83 of the relays in the group A'to respective segments 10, 30, 50, 7O and.90 oi the distributer E. A conductor 36, connected in derived circuit at a point on the generator loop oposite tothe connective point oi the conductor 35 with respect to the resistance unit 19, is connected to a collector ring '37 of the distributer. It will, therefore, be clear that in phase with the generation of each one of the five impulses corresponding with the present combination, the brush 38 of the distributer will be over a correspondingsegment, thereby establishing short circuit on the resistance unit 19. For the first impulse, this shunt circuit may be traced over the bus conductor 35, contacts 3 of the relay 2, the contacts 7 of relay 6, segment 10, brush 38, collector ring 37, thence by way of the conductor 36 to the opposite side of the resistance unit 19. It will be clear that for each of the remaining four impulses the resistance 19 will, in turn, be shortcircuited through similar paths extending through circuits controlled by respective ones of the relays B and C and the distributer E. Since each one of thefive impulses just described will be of.

39, in passing over the segments 55 and 56, operates the magnet 53 to advance the transmitter tape to a new combination of per forations, whereby at the group A contacts 1, 41 and 81 will be closed while contacts 21 and 61 will remain open. In the group B relays 2, 42 and 82 will be operated while the relays 22 and 62 will remain inert. $uch condition of the relays B effects at the group C, operation of relays 46 and 86 while relays 6, 26 and 66 remain inert. The operating circuit for the relay 46 may be traced from the left-hand side of a current source 31, a conductor 32, the contacts 5 of the relay 2, the contacts 24 of the relay 22, a conductor 52, thence through the winding of the relay 46 to the opposite side of the source 31. For the relay 86, the circuit extends from the left-hand side of a current source 71, a conductor 7 2, contacts 45 of the relay 42, contacts 64 of the relay 62, a conductor 92, thence through the winding of the relay 86 to the opposite side of the source 71.

The transmitting apparatus being retained in the position described, the first one of the five impulses will be of positive polarity and, due to the brush 38 being at a corresponding moment over the segment 10, a short circuit around the resistance unit 19 will be thereby established as already clescribed, therefore, this impulse will be incremented to a maximum strength. The

next impulse will be of negative polarity,

but, due to the relay 22 being inert, the c1rcuit from the segment 30 stands open at the contacts 23 of this relay. Therefore the resi stance unit 19 effects a predetermined mininiun'i strength for this negative impulse. For the third impulse, which is of positive polarity, a circuit may be traced by way of the bus conductor 35, the contacts 43 of the relay 42, contacts 48 of the relay 46, a sis-tance unit 49, segment 50 of the distributer, the brush 38, now at this segment, the collector ring 37 and conductor 36. It will be clear that the resistance unit 49. becomes effective through this circuit to form a parallel path around the resistance unit 19, thereby reducing or curbing this impulse below a maximum value, which would otherwise be present in carrying out the assumed code unit unuer consideration. For the fourth impulse the resistance unit 19 is effecto reduce this negative impulse to a minimum current strength. The fifth impulse of positive polarity instead of attaining a maximum incremented value, due to the operated position of the relay 82, will be curbed through the presence of a resistance unit 89 included through the contacts 88 of the relay 86 in the shunting pathformed over the segment 90 of the distributer in a manner similar to that described for the third impulse.

Referring to portion H of Fig. 2, the

curved shadow line 74 indicates the wave form of the five impulses of: current last described, in which the third and fifth impulses were curbed through the action of the controlling relays 46 and 86. The dotted curved line C 5 illustrates the wave form which would have resulted in the absence 01" curbing, as lied to the third and fifth impulses. The yted guide line 76 represents a wandering-zero present with the asymmetrical current condition which would result from uncurbed alternations indicated by the wave line 75. It will be understood that the resistance units D employed to effect curbing may be inductive and should be preferably of adjustable type to permit ready calibration of values to suitably meet the capacity and inductance characteristics of the cable with relation to the potential and frequency oi the signaling currents, etc.

Since the type and circuit arrangement of each one of the relays in the group B are typical one of another, and as the same is true with respect to the relays comprising the group C, it will be obvious that unless two incremented half-wave impulses, of either polarity, are separated by an incremented half wave of the opposite polarity, the second incremented half wave will be curbed or reduced in strength. t will also be clear that when two incremented impulses of either polarity are separated by an incremented impulse of inverse polarity, the

second incremented impulse corresponding tvith the first incremented impulse will not be curbed. In establishing operations for an incremented half wave a relay in the group B will always close a Circuit for the operation of a relay in the group C, and such C relay'will be located in the third position, in advance or to the right of the relay in the group B. To illustrate this; point, on operating to increment an impulse, relays 2, 22, 42, 62 and 82 01" the group B respectively close an operating circuit for corresponding relays 46, 66, 86, 6 and 26 in the group C. In turn, the order in which the relays in group C are secondarily disabled by the relays in the group B is always one position to the right, that is, in the group B, relays 2, 22, 42, 62 and 82 respectively disconnect relays 26, 46, 86 and 6 of the group C.

y In connection. with the relays 01': group C, it will be noted that the current sources 11, 3.1, 51 and 71, as interconnected through the relays 26, 46, 66 and 86, are in a closed loop circuit, and in order to prevent current action in this loop, it will be noted that the four current sources are connected to alternately oppose one another, thereby establishing a neutralizing or differential efiect in this circuit. A fifth source of current 91 serves to operate the relay 6, and for convenience is connected in the circuit which normally stands open at the contacts 65 of the relay 62.

Referring to Fig. 3 of the drawing, except for two windings on each one of the curbing relays 0, this alternate arrangement is the same as the transmitter equipment shown in Fig. 1, and for convenience of description, similar characters of reference have been employed to indicate like parts in this portion of the drawing. As indicated, each relay in the group G is marginally adjusted in such a manner that current must be present in both the right and lefthand winding, before the relay will operate. Tn describing the features of this arrangement, let it be assumed that a combination of impulses prepared at the contacts A, establish operation of relays 2, 42, and 82, while relays 22 and 62 remain inert. Operation of the relay 2, in addition to closing a circuit from the bus conductor 35 to the segment 10, also establishes a circuit from a source of grounded current 95, through contacts 5 of the relay 2 and the left-hand winding of the relay 46 to earth, and since the relay 22 is inert, its contacts 24 maintain the source95 through the right-hand winding of the relay 46 to earth. Such energization of the two windings of the relay 46 is cumulative and operates this relay to close its contacts 48, thereby connecting the resistance unit 49 in series with a connection established through the contacts 43 of relay 42 between the bus-conductor .35 and the segment 50. The contacts 45 of the relay 42 connect the source 95 through the left-hand winding of therelay 86, and contacts 64 of the relay 62 maintain the source 95 through the right-hand winding of relay 86 to earth. Therefore, cumulative current action in the relay 86 causes it to operate and through its contacts 88 to establish the resistance unit 89 in series with a connection extending from the segment 90 through the contacts 83 of the relay 82 to the busconductor 35. Through the cont-acts 85 of the relay 82, the source 95 is connected over the left-hand winding of the relay 26, but due to the right-hand winding of this relay being disconnected at the contacts 4 of the relay 2, it continues inert.

It will be clear that the conditions now present on the equipment will result in the distributer brush 38 effecting changes of current in the line 13 corresponding with a sequence comprising a positive impulse of maximum strength, a negative impulse of minimum strength, a positive impulse of curbed or reduced strength, a negative impulse of maximum strength and a positive impulse of curbed strength. On arriving at the segments 55 and 56, the clearing out brush 39 causes the magnet 53 to operate and advance the tape, thereby releasing the relays 2, 42 and 82, which in turn respectively permit the relays 46 and 86 to restore.

In the alternate arrangement, it will be noted that a single source of grounded current 95 is substituted for the five independent current sources 11, 31, 51, 71 and 91 employed in the first arrangement. Also that the normal contacts of each relay in the group B establish currentfrom the source 95 through the right-hand winding ofan associated relay in the group C, but since the latter relays are designed or adjusted for marginal operation only, they remain inert until a circuit is completed through both the right and left-hand windings as de scribed.

Since the arrangement shown on Fig. 3 may be substituted for the arrangement shown in 1 and as its features of operation, other than those already described, are the same as those of the first arrangement, further description of the system will not be necessary.

In the matter of interconnections between various combinations of relays, it will be mentioned that in a multiple): system, in which an even number of sending segments are employed, the interconnection between the transmitting relays and the modifying relays C may be completed by interconnecting the first relay of one group with the last relay of the other group Since telegraphic selectio is effected through different a'mplituoes of halfwave alternating currents, which may form asymmetrical wave currents, impulse receiving devices do not ordinarly discriminate between the polarity of the impulses. Therefore, in the case of signal transmission in which a five-unit code is employed, the groups of impulses would alternately change in the order of their polarity. In a four arm or quadruple); distributer having five impulse segments to a quadrant, the segments in each quadrant would be maintained in a fixed polarity relation to the currents developed by the alternating current generator, the first and second quadrants corresponding in polarities one with the other, while the third and fourth quadrants would correspond with each other but beof opposite polarity combinations as compared with the quadrants 1 and 2. In a similar manner each sextant of a sextu plex distributer would continue responsive to a uniform order of polarities, the polarity relations reversing in successive sextants. Such. relation would, of course, be present in a multiplex distributer of any capacity wherein an even number of arms or segment zones were present, and conversely the order of the polarities would reverse at each revolution of the trailer arm on distributers having an odd number of arms. t will be clear that in order to control impulse receiving devices adapted to discriminate between polarities as well as difi'erent current amplitudes, constant potential conditions may be readily secured as described in connection with a distributor, without idly consuming or wasting any impulse or half-wave current time.

It will be understood that the present invention may be readily applied to render the service described in connection with land lines when desirable, as in connection with long telegraph circuits, or on lines over which telephonic or message transmission by other methods of communication is carried on simultaneously. therewith.

l l hat is claimed is:

1. In a telegraph system, a line circuit, a transformer included therewith, a potential reducing means included with said transformer, a source of current waves included with said transformer and said potential reducing means, means for selectively con trolling the operative condition of said po- A ter ial reducing means in phase with said curr waves to effect signaling, and means for selectively curbing said current waves.

2. in a telegraph system, a line circuit, a

source ct r ternating current included therewith, a resistance, a plurality of selectable contacts, a olurality of first rela s controlled by said contacts, a distributer cooperating with said relays to render saic. resistance eticctive vary the amplitude of hali wave int ls oi' said alternating current to efiect a olurality of resistances, a second ality o clays controlled by said first to control said plurality of resistances tlier modify the amplitude of said half-waves in order to eliect the zero current condition of said line.

3. In a telegraph system, a line circuit, a source oi symmetrical current waves included therewith, means for-selectively renderng said wayes asymr ne trical to efiect signaling, means Ior modirying said asymmetrical waves to ZLilQCt the zero-current condition of said cabl and electroresponsive means controlled by said means for establishing said etrical effects to control the opera es of said modifying means.

4. in a telegraph system, a line circuit, a source of alternating current included therewith, potential modifying means in circuit with said source, a plurality of selectable contacts, a first plurality of relays controlled by said contacts, a distributor cooperating with said relays to control the operativeness ot said potential modifying means to vary the amplitude of half-wave intervals of said current to effect signaling, other potentialmodifying means, a second plurality of relays controlled by said first plurality of relays to operatively control said other potential modifying means to further vary the amplitude of predetermined ones of said half-Waves.

5. In a telegraph system, a line circuit, a source of alternating current included therewith, a plurality of selectable contacts, a plurality of first relays controlled by said contacts, a plurality of second relays con trolled in a predetermined order by said first relays, a distributor, a resistance unit successively controlled by said first relays and said distributor to selectively vary the amplitude of halt-wave intervals of said current to effect signaling, and a plurality of resistances controlled by said second relays to predeterminedly reduce the amplitude of certain half-waves of increased amplitude.

6. In a telegraph system, a source of alternating current, means for transmitting impulses, means for varying the strength of current emitted from said source, and electromagnetic means responsive to current impulses for ellecting the curbing of predetermined ones of the transmitted impulses.

7. A telegraph system comprising means for transmitting impulses, means for varying the strength of said impulses, a resistance normally incii'ective, and means responsi' e to current impulses for rendering said resistance effective to curb certain ones of the transmitted impulses.

8. In a telegraph system, a line circuit, a source of alternating current normally connected therewith, means for transmitting impulses, means adapted to vary the amplitude of half wave intervals of said current, and means rendered effective by local current impulses for thereby selectively curbing predetermined ones of the transmitted impulses.

9. In a telegraph system, means for transmitting impulses, a plurality of relays operative for varying the strength of said impulses, and means operated by certain ones of said relays for curbing predetermined ones of said impulses.

ln witness whereof l hereunto subscribe my name this 5th day of October, A. D. 1917.- 

